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VFat patent could be invalidated, thanks to Motorola and Torvalds

According to an article in Wired, Microsoft may have to face the fact that it will no longer be able to enforce its patent number 5,758,352 ("Common name space for long and short filenames"). The report describes a dispute between Microsoft and Motorola before the US International Trade Commission (ITC), in which Motorola was initially found guilty of infringing four Microsoft patents.

One of the patents invoked by Microsoft in the case was patent number 5,758,352, which describes a technique for storing long filenames in FAT file systems which were not designed for the purpose. The tricks for achieving this described in the patent were used in the VFat version of the file system.

ITC Administrative Law Judge Theodore R. Essex rejected Microsoft's claim, however. Motorola has asserted prior art on the basis of discussions on the storage of long filenames in FAT in public newsgroups three years prior to submission of the patent. One of the two newsgroup postings was dated March 1992 by a poster identified only as 'Natuerlich!'. The second was posted by Linux creator Linus Torvalds in December 1992. Torvalds also testified in the course of the dispute between Microsoft and Motorola.

The ITC's decision not to recognise the FAT patent in the Motorola case does not in itself invalidate the patent. The ruling was only an initial determination as part of a wider dispute involving a number of Microsoft patents and Motorola. A committee is currently reviewing the decision as a whole and will give its ruling on 20 April.

Althought the ITC is a first port of call for many patent disputes, because of the speed of decision making and the ability to block the import of infringing products into the US, ITC decisions are not legally binding on the US court system, but they do tend to be listened to by civil courts. The decision may also have consequences for a dispute with Barnes & Noble in which this is one of several patents invoked by Microsoft. The patent was also cited in a 2009 dispute with TomTom.